Immune checkpoint inhibitor-associated new-onset hypophysitis: a retrospective analysis using the FAERS.

Background: Our study aimed to investigate the prevalence and demographic characteristics of immune checkpoint inhibitor-associated hypophysitis (ICI-hypophysitis) using data from the FAERS, and the risk factors of prognosis were explored.

Methods: In this retrospective study, all cases of newly-diagnosed hypophysitis associated with FDA approved ICIs from 1st January 2007 to 31st December 2022 were accumulated using FAERS. Demographic data including age, sex, body weight, the prognosis of cases, and other co-occurred endocrinopathies induced by ICIs were analyzed and compared between different subgroups of immunotherapy.

Results: The reporting frequency of ICI-hypophysitis was 1.46% (2343/160089). Patients on the combination therapy had higher risk of hypophysitis reporting, followed by anti-CTLA-4 agent compared with other monotherapies (p < 0.001). Male subjects displayed higher reporting risk of ICI-hypophysitis (p = 0.015). Patients on anti-PD-1 therapy or the combination therapy showed higher occurrence rate of type 1 diabetes (anti-PD-1 vs. anti-PD-L1 vs. anti-CTLA-4 vs. combination therapy, 4.2% vs. 0.7% vs. 0.3% vs. 8.4%, p < 0.001). The occurrence rate of new-onset thyroid diseases in patients receiving combination therapy was higher than anti-PD-1 monotherapy (12.3% vs. 8.4%, p = 0.010). Elder age, lung cancer, and renal cancer emerged to be positively associated with severe clinical outcomes [>65 years, OR 1.042, 95%CI (1.022-1.063), p < 0.001; lung cancer, OR 1.400, 95%CI (1.019-1.923), p = 0.038; renal cancer, OR 1.667, 95%CI (1.153-2.412), p = 0.007]. Anti-CTLA-4 monotherapy was discovered to be a protective factor of severe outcomes [OR 0.433, 95%CI (0.335-0.558), p < 0.001]. Female sex and co-occurrence of ICI-related diabetes exhibited lower risk of death [female, OR 0.571, 95%CI (0.361-0.903), p = 0.017; diabetes, OR 0.090, 95%CI (0.016-0.524), p = 0.007].

Conclusions: ICI-induced hypophysitis is male-predominant irAE, most commonly seen in patients on anti-CTLA-4 mono- or combination therapy. Awareness among clinicians is critical when patients with elder age, lung or renal cancer develop hypophysitis, which indicates poor clinical outcomes. Female sex, anti-CTLA-4 monotherapy and co-occurrence of ICI-related diabetes are protective risk factors for poor prognosis.